Pradimicin A (PRM-A) and related compounds constitute an exceptional family of natural pigments that show Ca²⁺-dependent recognition of d-mannose (Man). Although these compounds hold great promise as research tools in glycobiology, their practical application has been severely limited by their inherent tendency to form water-insoluble aggregates. Here, we demonstrate that the 2-hydroxyethylamide derivative (PRM-EA) of PRM-A shows little aggregation in neutral aqueous media and retains binding specificity for Man. We also show that PRM-EA stains glycoproteins in dot blot assays, whereas PRM-A fails to do so, owing to severe aggregation. Significantly, PRM-EA is sensitive to glycoproteins carrying high mannose-type and hybrid-type N-linked glycans, but not to those carrying complex-type N-linked glycans. Such staining selectivity has never been observed in conventional dyes, suggesting that PRM-EA could serve as a unique staining agent for the selective detection of glycoproteins with terminal Man residues.

中文翻译：

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用于糖蛋白检测的基于普拉迪霉素的染色染料

Pradimicin A (PRM-A) 和相关化合物构成了一个特殊的天然色素家族，它们显示出 Ca ²⁺依赖性识别d-甘露糖（男人）。尽管这些化合物作为糖生物学的研究工具具有广阔的前景，但它们的实际应用受到其形成水不溶性聚集体的固有倾向的严重限制。在这里，我们证明 PRM-A 的 2-羟乙基酰胺衍生物 (PRM-EA) 在中性水性介质中几乎没有聚集，并保留对 Man 的结合特异性。我们还表明 PRM-EA 在斑点印迹分析中染色糖蛋白，而 PRM-A 由于严重聚集而未能这样做。值得注意的是，PRM-EA 对携带高甘露糖型和混合型 N-连接聚糖的糖蛋白敏感，但对那些携带复合型 N-连接聚糖的糖蛋白不敏感。在传统染料中从未观察到这种染色选择性，